While the world is still heavily reliant on fossil fuel sources such as coal, oil and natural gas, a tremendous amount of money and research has poured into alternative energy in recent decades. Investors and casual observers are well aware of wind energy and solar energy as two renewable, clean energy sources that could help shoulder the global energy burden in an environmentally responsible way.
However, while solar and wind energy seem to get the majority of the media headlines, an entire segment of the alternative energy sector is looking away from the sun and skies and focusing its attention on the power of the world’s oceans.
Any sailor that has ever endured a storm at sea can certainly recognize the awe-inspiring power that ocean waves produce. In fact, the idea of harnessing the ocean’s energy was originally inspired by the rise and fall of massive ships. The first ocean power-related patent was filed way back in 1799. “If … one imagines this [ocean liner] suspended from the end of a lever, one will conceive the idea of the most powerful machine which has ever existed,” the patent reads.
Unfortunately, centuries later, the world is still working on a design that can capture the full potential of wave power. The world’s first commercial wave power device wasn’t completed until 2000. The Islay Limpet in Scotland is a 250 kW oscillating water column generator powered entirely on ocean waves. As waves from the ocean enter an on-shore chamber, the waves compress the air in the chamber. The compressed air is then forced through a “blowhole” and turns a power-generating turbine.
The design of the station is impressive, but its output isn’t. According to the Solar Industries Association, 250 kW is enough power for roughly 41 average U.S. homes.
However, other companies are taking a very different approach to wave power.
Ocean Power Technologies has secured two new contracts worth more than $1.2 million with Mitsui Engineering and Shipbuilding and the U.S. defense department. The contracts are related to Ocean Power Technologies’ latest PowerBuoy device, the PB3. The PB3 consists of a float that sits on the surface of the ocean, a metal plate that rests about 100 feet below the surface, and a large, piston-containing hydraulic cylinder connecting the two. The motion of the waves pushes and pulls on the piston to generate power.
Ocean Power’s new contracts suggest that there is real potential for wave power technology. Unfortunately, it may take quite a while to realize that potential.
According to George Hagerman, senior research associate with the Center for Energy and the Global Environment at Virginia Tech, wave energy has a lot of ground to make up to compete with solar, wind or fossil fuel energy. “Ocean wave energy conversion is at the stage where land-based wind was in the late 1970s,” Hagerman says. It took wind energy technology decades to become competitive with fossil fuel generation.
Paul Soskin, project director for the upcoming 10th annual International Tidal Energy Summit in London, agrees that wave energy is still in its infancy. “The energy is there, though, it’s just a case of tapping into it and cracking the technology”, Soskin says. In the meantime, he believes wave energy’s more advanced cousin, tidal energy, could pave the way. “Hopefully, as the business case for tidal gets proven (regulation, grids, tariffs etc), this will in turn catalyze the development of wave power,” says Soskin.
The near-term focus for companies developing wave power technology will be improving efficiency. If wave power is not economically viable, it doesn’t matter how innovative the technology is. Robert Thresher, research fellow at the National Renewable Energy Laboratory, says that it’s too early to predict how much of a global impact wave energy could have. “Cost estimates for wave energy are not very reliable at this time because the technology is still young and there are no commercial plants in operation,” Thresher says. One recent report estimated that wave energy costs need to be reduced by 50 percent from current levels before it becomes competitive with other leading energy sources.
Even the U.S. Department of Energy seems to recognize the risks of wave energy investment at this stage. A spokesman says the department is evaluating the viability of different types of marine and hydrokinetic energy devices.
The appeal of wave energy as a nearly unlimited green, renewable power source is undeniable. Unfortunately, at this point in the technology’s development, there are simply too many unknowns to make wave energy a responsible investment.